Re: measuring very low ripple and noise in switchers
The reason I mentioned the source in your other thread (you only need one...) isn't so much about noise, but that it doesn't have its own switching ripple which contributes to the output seen on the DUT (the supply you're testing). You want the DUT to be operating at an absolutely constant duty cycle, so the input voltage should be solid. So yeah a battery would be nice, if it works. But any supply can probably be made to work with proper filtering. But be wary of benchtop switching supplies.